Objective To investigate the impact of cyclosporine A (CsA) on atrial expression change of L-type calcium channel αlc subunit in a canine model of atrial fibrillation (AF). Methods AF was induced by rapid atrial pacing (400 baets/min) for 8 weeks in adult male dogs and placebo (n=6) or CsA (5 mg·kg-1·d-1, n=6) were orally administered to these animals. Sham operated animals served as normal controls (n=6). The atrial electrophysiological parameters including P wave duration, atrial effective refractory period (AERP) were recorded and analyzed at baseline and 8 weeks later. Animals were scarified at 8 weeks post final electrophysiological examinations and atrial expressions of L-type calcium channel αlc subunit were determined by Western blot. Results Compared to sham group, the P wave duration was significantly prolonged while AERP was significantly decreased in AF and CsA groups (all P <0. 05). AERP was significantly longer in CsA group than that in AF group (P < 0. 05 ). L-type calcium channel αlc subunit expression was significantly downregulated in AF group compared to sham group (P <0. 05) and CsA significantly attenuated this downregulation (P < 0. 01 vs. AF group). Conclusion CsA could attenuate the downreguahion of the L-type calcium channel αlc subunit expression and improve the atrial electrophysiological remodeling in this canine model of AF.%目的 研究环孢素A(CsA)作用下心房颤动(房颤)犬心房电生理特性及心房L型钙离子通道蛋白αlc亚单位(Lαle)表达变化.方法 实验犬分为CsA组、房颤组及假手术组(Sham组),快速起搏心房建立犬房颤模型,记录标测并对比各组起搏前后P波时程、心房有效不应期(AERP)的差异,应用Western blot免疫印迹技术比较各组问Lαlc表达的差异.结果 房颤组、CsA组较Sham组P波时程延长(P<0.05),AERP缩短P<0.05).CsA组较房颤组AERP延长(P<0.05).房颤组较Sham组Lαlc表达明显降低(P<0.01).CsA组较房颤组Lede升高(P<0.01),CsA组与Sham组之间差异无统计学意义.结论 CsA 应用逆转了房颤犬心房Lαlc表达变化并改善了心房电生理重构,可能会在房颤的治疗中发挥积极的意义.
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